The Solvay Conference, founded by the Belgian industrialist Ernest Solvay in 1912, was considered a turning point in the world of physics. Located in Brussels, the conferences were devoted to outstanding preeminent open problems in both physics and chemistry.

Perhaps the most famous conference was the October 1927 Fifth Solvay International Conference on Electrons and Photons, where the world’s most notable physicists met to discuss the newly formulated quantum theory. The leading figures were Albert Einstein and Niels Bohr.

Einstein, disenchanted with Heisenberg’s uncertainty principle, remarked “God does not play dice”. Bohr replied, “Einstein, stop telling God what to do”. 17 of the 29 attendees were or became Nobel Prize winners, including Marie Curie, who alone among them, had won Nobel Prizes in two separate scientific disciplines.

This conference was also the culmination of the struggle between Einstein and the scientific realists, who wanted strict rules of scientific method as laid out by Charles Peirce and Karl Popper, versus Bohr and the instrumentalists, who wanted looser rules based on outcomes. Starting at this point, the instrumentalists won, instrumentalism having been seen as the norm ever since, although the debate has been actively continued by the likes of Alan Musgrave. [source]